[Numpy-discussion] Reading 12bits numbers ?

Martin Raspaud martin.raspaud@smhi...
Tue Jun 8 10:03:12 CDT 2010


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Nadav Horesh skrev:
> You can. If each number occupies 2 bytes (16 bits) it is straight
> forward. If it is a continues 12 bits stream you have to unpack by your
> self:
> 
> data = np.fromstring(str12bits, dtype=np.uint8)
> data1 = data.astype(no.uint16)
> data1[::3] = data1[::3]*256 + data1[1::3] // 16
> data1[1::3] = (data[1::3] & 0x0f)*16 + data[2::3]
> 
> If you have even number of 12 bits you can continue as the follows:
> 
> result = np.ravel(data1.reshape(-1,3)[:,:2])
> 
> I might have mistakes, but I hope you grasped the idea.

Thanks a lot.

I was more thinking along the lines of having a special dtype that would read 12
bits at a time, but I couldn't find anything, and you confirmed that I had to
unpack myself.

I'll try your solution, thanks again,

Martin
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